SIEM systems are powerful — but not for every situation. This page shows when a SIEM is the right choice, and when an alternative gets you to an answer faster, more affordably, and more independently.
15 minutes. No sales call.
A SIEM is the standard solution for continuous security monitoring in larger organizations. It correlates logs from many sources, detects patterns, and supports compliance requirements. If you need permanent monitoring with central data retention, a SIEM is the right tool.
This page isn't an argument against SIEM. It's an argument for choosing the right tool for the situation at hand.
But there are situations where a SIEM becomes the wrong answer — either because the effort doesn't match the task, or because the system's architecture can't answer a specific question clearly.
In practice, we keep seeing the same patterns:
Implementation time exceeds the need
A SIEM typically takes several months from selection through integration to production. Use-case engineering, log onboarding, tuning, and training add up. In situations where clarity is needed within days — after a security incident, say — that speed comes too late.
License, implementation, ongoing operation
SIEM licenses are typically billed by GB/day, events per second, or connected assets. On top come implementation costs for use-case engineering and integration, plus ongoing staffing for maintenance and tuning. In total, SIEM projects for mid-market organizations can reach six figures per year — without any guarantee that the right data is in the logs after an incident.
Staffing for ongoing operation
A SIEM isn't a tool you install and walk away from. It needs ongoing care: new use cases, tuning against false positives, adaptation to new data sources. The cybersecurity talent shortage is acute — the US alone faces a multi-million-person gap — and smaller organizations or MSSPs without a dedicated SOC hit their limits fast.
Protection and analysis from the same source
When detection, protection, and assessment all happen in the same system, a second perspective is missing. A system that missed an attack won't necessarily find that same attack on review. Especially after an incident — where what matters is whether residual activity is still running — an independent view is often the decisive point.
Detection gaps aren't an isolated phenomenon — they're systemic.
A 2025 analysis by CardinalOps, based on 13,000 detection rules and over 2.5 million log sources, shows that SIEM systems cover on average only 21 percent of the MITRE ATT&CK techniques used by attackers — 79 percent go undetected.
There are clear situations where a SIEM is the right step.
You need permanent, centrally correlated monitoring across many data sources.
Compliance requirements demand continuous log collection with retention periods.
You operate a dedicated SOC with staff for use-case engineering and tuning.
You want to build a long-term data foundation for threat analysis and forensics.
In these cases, a SIEM isn't just the right choice — it's the only one.
Anyone looking for a SIEM alternative usually has a clear trigger: an incident, a quiet suspicion, an open question about the current situation. To serve that trigger, an alternative must meet four criteria:
No multi-week implementation project. Connection and first insights within days, not months.
The network view stands on its own and changes nothing in your existing systems — that's why it delivers a real second perspective after an incident. On request, further sources (e.g. EDR, firewall) can be added to complete the picture.
The goal isn't another data stream, but a concrete answer to a concrete question.
Continuous as a subscription or point-in-time per engagement — no per-GB license, no long-term lock-in.
AEGYS Monitor is a passive Network Detection and Response (NDR) solution. The appliance connects via SPAN or TAP and delivers an independent view of actual network communication — either as a point-in-time reality check or as a continuous NDR subscription. The full product description is on the Monitor page.
Passive capture via SPAN port or TAP. No agents, no interference with your systems — the network view stands on its own. Further sources can be added when needed.
First anomalies usually within hours. A reliable assessment depending on network size and activity — without a multi-week implementation project.
AEGYS Monitor can be used as a point-in-time reality check or as a continuous NDR subscription — no per-GB license, no minimum term.
AEGYS Monitor is the fast, independent entry point via the network view — without a SIEM project. Where more is needed, further sources can be added and existing investments made more valuable, instead of being replaced.
| Criterion | Classic SIEM | AEGYS |
|---|---|---|
| Goal | Continuous monitoring | Continuous view — or point-in-time clarity on demand |
| Time-to-value | Weeks to months | Hours to a few days, no implementation project |
| Setup | Project with use-case engineering | Connect it, it runs |
| Data basis | Logs from connected sources | Direct, passive network view as the basis — extended with further sources on request (e.g. endpoint) |
| Data sovereignty | Data in a central system, often cloud-based | Captured passively on your premises; metadata encrypted to the analysis location you choose — US or Germany, no third countries you didn't pick, no hyperscaler cloud |
| License model | Per GB / EPS / asset, plus implementation and operation | Engagement-based or subscription, no per-GB license |
| Staffing | Dedicated SOC or SIEM team | No dedicated SOC team required |
| Post-incident fit | Limited — only if connected beforehand | Ready to use immediately |
| Typical use | Permanent security infrastructure | NDR, compromise assessment, second opinion, acute clarification |
Goal
Classic SIEM
Continuous monitoring
AEGYS
Continuous view — or point-in-time clarity on demand
Time-to-value
Classic SIEM
Weeks to months
AEGYS
Hours to a few days, no implementation project
Setup
Classic SIEM
Project with use-case engineering
AEGYS
Connect it, it runs
Data basis
Classic SIEM
Logs from connected sources
AEGYS
Direct, passive network view as the basis — extended with further sources on request (e.g. endpoint)
Data sovereignty
Classic SIEM
Data in a central system, often cloud-based
AEGYS
Captured passively on your premises; metadata encrypted to the analysis location you choose — US or Germany, no third countries you didn't pick, no hyperscaler cloud
License model
Classic SIEM
Per GB / EPS / asset, plus implementation and operation
AEGYS
Engagement-based or subscription, no per-GB license
Staffing
Classic SIEM
Dedicated SOC or SIEM team
AEGYS
No dedicated SOC team required
Post-incident fit
Classic SIEM
Limited — only if connected beforehand
AEGYS
Ready to use immediately
Typical use
Classic SIEM
Permanent security infrastructure
AEGYS
NDR, compromise assessment, second opinion, acute clarification
SIEM projects for mid-market organizations carry significant cost — beyond license and implementation, especially ongoing staffing for use-case engineering and maintenance. The exact range depends heavily on data volume, number of connected systems, and operating model. AEGYS works engagement-based — we discuss specific terms in the intro call.
Both tools have their place. The question isn't which is better, but which fits your current task.
After a security incident or on a quiet suspicion: a fast, independent assessment of network activity, without starting a new SIEM project. Also as a second opinion on your own security posture — without changing your existing infrastructure.
Fast clarity for customers who don't run their own SIEM, or where a SIEM deployment is out of proportion to the trigger. An additional service without building your own infrastructure — and without the customer having to adopt a long-term tool.
A 15-minute intro call. We understand your situation and check with you whether AEGYS is the right answer — or whether another path makes more sense. If AEGYS fits, we deploy promptly.
15 minutes. No sales call.
Also for MSSPs and security partners.